Conventional technology relating to the present invention includes, for example, as described in Japanese Patent Laid-Open No. 2002-227727, an abnormality detection device for detecting an abnormality in an exhaust gas recirculation apparatus (hereunder, also referred to as “EGR (Exhaust Gas Recirculation) apparatus”). An abnormality detection device according to the aforementioned conventional technology has a function that estimates a value (size) of an intake pressure when the EGR apparatus operates normally. Unless an abnormality occurs in the EGR apparatus, since an appropriate amount of exhaust gas is recirculated to the intake passage, the estimated value and the actual intake pressure in the intake passage should be approximately the same. Therefore, the above described conventional abnormality detection device compares the estimated intake pressure and a detected intake pressure of an intake pressure sensor, and determines that there is an abnormality in the EGR apparatus when a deviation between the two values is greater than or equal to a predetermined value.